Transfer apparatus



June 16, 1953 v c oss 2,642,179

TRANSFER APPARATUS Filed July 25, 1947 8 Sheets-Sheet 1 June 16, 1953 R.E. cRoss 2,642,179

TRANSFER APPARATUS Filed July 25, 1947 8 Sheets-Sheet 2 F 4/21 Crass.

BY Ma?" June 16, 1953 R. E. CROSS 2,642,179

TRANSFER APPARATUS Filed July 25, 1947 s Sheets-Sheet 3 R4475 Crass.

June 16, 1953 R. E. cRoss TRANSFER APPARATUS 8 Sheets-Sheet 4 Filed July25, 1947 I TOR/VEKST June 16, 1953 E. @055 2,642 179 TRANSFER APPARATUSFiled July 25, 1947 8 Sheets-Sheet 5 20: w me IN V EN TOR. fia/yl 1Cross.

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R. E. CROSS TRANSFER APPARATUS June 16, 1953 s Sheets-She et 6 FiledJuly 25, 1947 INVENTOR. J Crass" June 16, 1953 312055 2,642,179

TRANSFER APPARATUS A Filed July 25, 1947 8 Sheets-Sheet 7 IN V EN TOR.fiaZv/F J. Cramv June 16, 1953 R. E. CROSS TRANSFER APPARATUS Filed July25, 1947 8 Sheets-Sheet 8 )mw B w w g Q I W A J'lih o I J N R 0 WPatented June 16,

OFFICE TRANSFER APPARATUS Ralph' E., Cross, Grosse Pointe, Mich.Application July 25, 1947, Serial N 0. 763,531

3 Claims. 1 This invention relates broadly to transfer apparatus andmoreparticularly to apparatus of this character which is adapted totransfer workpieces progressively through a series of work stations. vAnimportant object of the present invention is to provide an apparatuswhich will pick up a workpiece from one work station, transferitlaterally to an adjacent station, deposit it, and then return to thefirst station.

Another object of the invention isto providean apparatus of theabove-mentioned character which can be easily adapted to handle manytypes of work. J Still another object of the invention is to provide anapparatus of the above-mentioned character having means forautomatically positioning workpieces properly with respectto a workstation adjacent thereto.

Yet another object of the invention is to provide an apparatus of theabove-mentioned character which is automatic in operation.

, A further object of the invention is to pro- .vide an apparatus of theabove-mentioned character which can be readily ontrolled. by mechanismin the work station to cycle automatically .as soon as the operation tobe performed in that .particular station is completed. r A still furtherobject of the invention is to' provide an apparatus of theabove-mentioned character having means for positioning theworkpieceduring that portion of the cycle when it is transferred from one workstation to another.

A yet further-object of the invention is, to pro vide an apparatus ofthe above-mentioned character which is simple but rugged in constructionand relatively inexpensive to manufacture.

Other objects and advantages of the invention will be apparent duringthe course of the following description. I

In the drawings forming a part of this specification and wherein likenumerals are employed 'to designate like part throughout the same:

' Fig. 1 is a top plan view of a. transfer apparatus embodying one formof the invention;

Fig. 2 is a vertical sectional view taken on the line 2-2 of Fig. l;

a Fig. 3 is a fragmentary, vertical sectional view taken on the line;33of Fig. 2;

Fig. 4 is a fragmentary, vertical sectional view *taken on the line- 4-4of Fig. 2; Y a Fig. 5 is a fragmentary, vertical sectional view taken onthe line 5-5 of Fig. 1; i Fig. 6 is a fragmentary, vertical sectionalview -taken on the line 66 of Fig. 1; v H

10A; and

spect to Fig. 7 is a schematic view of the control system for thetransfer apparatus;

Fig. 8 is a partial View showing the positioning of certain of the limitswitches and the actuators therefor; v

Fig. 9 is a partial view showing the positioning of certain other of thelimit switches and the actuators therefor;

Figs. 10A and 10B illustrate leftand righthand portions respectively ofa modified transfer apparatus embodying the invention;

Fig. 11 is an enlarged, fragmentary, vertical sectional View taken onthe line II--Il of Fig. 10A;

Fig. 12 is an enlarged, fragmentary, vertical sectional view taken-ontheline I 2l 2 of Fig. 11; Fig. 13 is an enlarged, vertical sectional viewtaken on the line [3 -13 of Fig. 10A;

Fig. 14 is an enlarged, vertical sectional view taken on the line |4I4of Fig. 10A;

Fig. 15 is an enlarged, fragmentary, horizontal sectional view taken onthe line l5l5 of Fig. 10A; v

Fig. 16 is a fragmentary, vertical sectional view taken on the lineIii-l6 of Fig 15;

Fig. 17 is averti'cal, transverse sectional View taken on the line ll-llof Fig.10A;

Fig. 18 is a vertical, longitudinal sectional view taken on the linel8-l8 of Fig. 17;

Fig. 19 is anenlarged, fragmentary, vertical sectional view taken on'theline l9l9 of Fig.

Fig. 20 is a schematic view of the control system for the modifiedtransfer apparatus. -35

theinvention comprises an apparatus for moving workpieces qautomatically from Considered in certain of its broader aspects,

v a one work station to another and progressively through a series ofworkstations. The work stations must be uniformly spaced and usually areoccupied by machines which perform some operation on the work; however,;the stations'may merely contain supports which hold idle workpiecesbetween machining operations or they may contain apparatus forpositioning the work properly with rea machine in the next succeedingstation. v

= In general, the apparatus comprises stationary worksupports in eachwork station, transfer dev ces having a horizontally movable slideequipped with workfholding members, and hoists for raising and loweringthe slide to move the work-holdingmem-bers between positions above andbelow the stationary work supports." Means is provided for shifting theslide horizontally and 3 for properly-controlling the movements both ofthe slide and of the hoists. By properly coordinating the movements ofthe various mechanisms, the apparatus can be made to cycle automaticallyeither continuously or intermittently under the control of a manualstarter switch.

At the beginning of a cycle, the apparatus is positioned with the hoistslowered, the slide retracted, and the work-holding members positioned toengage workpieces on the stationary work supports. In operation, theslide is first raised by the hoists to lift the work-holding membersfrom a position below to a position above the stationary work supportsso that the members pick up workpieces from the supports. The slide isthen moved horizontally in the manner hereinabove described to transferthe workpieces to adjacent work stations, and the hoists are thenlowered to deposit the workpieces on the stationary supports in thelast-mentioned stations. To complete the cycle of operation, the slideis returned either with the hoist in lowered position or the motionshereinabove described are reversed with the work-holding memberspositioned to release or disengage the work- 1 pieces depending uponexigencies of the particular situation. The above steps are performedsimultaneously in all of the work stations, and after each cycle ofoperation, an unfinished workpiece is placed either manually or bysuitable mechanical means on the first station at one end of theapparatus, and a finished workpiece is removed from the last station atthe opposite end thereof.

The apparatus shown in Figs. l-9 was designed primarily for transferringpipe or the like; however, it is not intended that the apparatus belimited to this use, as it may be employed in any capacity where anapparatus Of this character has utility. In the apparatus here shown byway of illustration only four work stations designated generally by thenumerals 20, 22, 24, and 26 are shown, but it will be readily apparentthat the apparatus can be easily adapted to operate with any desirednumber of stations. Also, it will be observed that in the illustrationall four stations are at one side of the transfer device. Thisarrangement, however, is not essential, since if desired, certain of thework stations may be at one side of the transfer device and other workstations at the other side thereof.

Work stations 22 and 26 are occupied by maehines'for performing certainoperations on the workpieces, work station contains apparatus forpositioning the work'properly withrespect to the machines in station 22,and work station 24 is merely an intermediate idle station in which nooperations are performed on the work. The specific construction andoperation of machines in stations 22 and 26 are conventional andcomprise no part of -the present invention. They are shown merely by wayof illustration, and since they are incidental to the invention adetailed description thereof is not necessary.

The apparatus here shown is adapted to transfor two workpieces side byside simultaneously through work stations 20, 22, 24, and 26. In thisconnection, however, it will be readily apparent that the apparatus canbe readily adapted to handle a single workpiece in each work station orto handle three or more workpieces simultaneously in each work station.V

The first work station 20 comprises a series of rollers 28 which supportthe workpieces (not :shown) and a vertical stop 30 at one 'end or therollers 28. In operation, the stop 30 abuts one end of the workpiecesand positions the latter properly with respect to the machines inadjacent work station 22. As best shown in Fig. 1, the rollers 23 arearranged in pairs and the two rollers in each pair are fixed on a shaft32, which shaft is supported at its ends by standards 34 (Fig. 5) and iscontinuously driven by a motor 36 through gears 38 and 40 and an endlesschain 42. Corresponding rollers 28 in each pair are disposed inalignment with each other, so that a pipe or other workpiece ofelongated structure can be laid thereon and collectively supportedthereby.

Thus, in the work station 20 here shown, two pipes are placed side byside on the two series of rollers 28, and motors 36 continuously rotatethese rollers in a direction to move the workpieces axially against thestop 30. The workpieces may be loaded on the rollers 28 either manuallyor mechanically by apparatus well known in the art, and, in practice,they preferably are placed on the rollers in approximately the desiredposition with respect to the stop 30. Thus, the axial travel imparted tothe workpieces by the rollers 28 is relatively short, and as aconsequence, the rollers can be rotated relatively slowly. The rollerscontinue to rotate after the workpieces have moved against stop 30 andhold the workpieces so positioned until they are picked up by thetransfer device.

The apparatus for transferring the workpieces from one work station toanother comprises stationary Work holders 44 and transfer devices 46arranged alternately in laterally spaced relation at one side of therollers 28 and extending across the entire series of work stations 20,22, 24, and 2'5. In'the embodiment of the invention here shown, threestationary work holders l4 are provided between four transfer devices46. In this connection, however, it will be readily understood that thenumber of work holders 44 or transfer devices 46 is not critical andthat any number of these units required to handle a particular workpiececan b provided. Also, in many instances it may not be necessary toprovide a stationary work holder 44 between each pair of transferdevices 46. For example, if the workpieces are uniformly long and rigid,two work holders at opposite ends of the apparatus may be sufiicient. Onthe other hand, if some of the workpieces are relatively short or areflexible in character, it may be necessary to provide more than'onestationary work holder'44 between each pair of adjacent transfer devices46.

For a specific description of the stationary work supports 44 referenceis had to Fig. 6. All of the supports 44 are identical in construction,and a detailed description of one therefore will suffice.

Each support 44 comprises a horizontal beam 58 which is supported atspaced intervals by upright standards 50 and carries a plurality ofuniformly spaced upstanding V-blocks 52. All of the supports 44 are ofuniform height and the height is determined by the character of themachines in stations 22 and 2B. In practice, the workpieces rest on theV-blocks 52 and these blocks should position the workpieces for properengagement by the machines. Since the workpieces are supported byrollers 28 in work station 20, the supports 44 extend only across workstations 22, 24, and 26. Two V-blocks 52 are provided on each beam "48for each of the work stations '22, 24, and 26, and the V-blo'cks arespaced uniformly with respect to each other and with respect to therollers 28.

For a detailed description of the transfer devices 46 reference is hadto Figs. 2, 3, and 4. .All of the transfer devices 46 are identical inconstructionan-d operation, and'a detailed description of one thereforeis sufiicient.

Each transfer device 46 comprises a slide 54 mounted for horizontaltranslatory movement on a supporting beam 56. The beam 56, in turn, iscarried by and supported on two hoists 58 located adjacent opposite endsthereof. Slide 54 carries a row of V blocks 68 which are uniformlyspaced on the same centers as V-blocks 52, and provision is made fordriving these slides back and forth onv the beam'56 a distance equal tothe distance be- .tween adjacent work stations 20, 22, 24, and 26.

At one end of its horizontal travel, slide 54 is positioned with the twoendmost V-blocks 60 in alignment with respective rows of rollers 28, andat the other limit of its travel, the two V-blocks 50 referred to aboveare positioned in alignment with th two endmost v-blo-cks 52 onthestationary work holders 44. Hoists 58 raise and lower the slideassembly to move the V-blocks 66 between positions above and below theV-blocks 52.

At the beginning of a cycle of operation, slide 54 is retracted amaximum distance to the left as shown in Fig. 2 so that the two endmostV- blocks 62 are aligned with. the two series of rollers 28 -(Flg. l),and the hoists 58 are lowered to position V-blocks 56 below rollers 28and also below the V-blocks 52. Two workpieces are then placed onrespective rollers 28 and are immediately 48 from whi-clrzthey' areremoved either manually or by suitablemechanical means before thetransfer device completes anothercycle of operation.

scription of the same reference is had to Figs.

2-4. The slide 54 is shown in the form of an I-beam (Figs. 3 and 4), andthe V-blocks 60 are welded or otherwise fastened permanently on. theupper flange thereof. The support 56 comprises a pair. of channels 62arranged in parallel,

- spaced relation below the slide 54 and fastened shifted longitudinallyby the latter against the 1 stop 35, which stop positions them forproper engagement with the machine in work station 22.

As soon as the workpieces engage stop 38, the transfer device operatedto transfer them to work station 22. As the transfer device begins itscycle of operation, the hoists 38 raise the slide 54 and its supportingbeam 56 sufiiciently to move .V-blocks 60 to a position above rollers28. As V- blocks 68 rise to a position above the rollers 28, they pickup the workpieces and lift them sufficiently to clear the rollers. Whenhoists 58 reach the upper limit of their travel, the slides 54 are movedsimultaneously to the right, as viewed in Fig. 2, to position theworkpieces directly above the first two V-blo-cks 52 and in alignmentwith respective machines in work station 22. Hoists 58 are'then moveddownwardly a distance sufiicient to position V-blocks 65 below V-blocks52. Manifestly, when V-blocks 60 move below the V-blocks 52, workpiecescarried thereby are deposited on the stationary work supports 48 and areentirely released by V-blocks 60. As soon as hoists 58 reach the lowerlimit of their travel, slides 54 traverse to the left as viewed in Fig.2 to their initial or starting position. As suggested, two workpiecesare then placed on the rollers 28 preparatory to another cycle ofoperation by the transfer device, while the two workpieces which weretransferred to work station 22 are acted upon by the machines in thelatter station.

From the foregoing, it will be readily apparent that each operation ofthe transfer devices 46 moves workpieces from any or all of workstations 20, 22, 24,.and 26 to the next succeeding work station. Theworkpieces are moved in groups of two and all of the workpieces aremoved simultaneously. Those workpieces removed from the endmost workstation 26 are deposited on the two endmost: V-blocks 52 of stationarysupports solidly together by. a'transverse bar64. Rollers 66 carriedbyand located at opposite sidesof the I-beam 54 travel on wear plates 68welded or otherwise fastened on the upper flanges of channels 62. Wearplates 68 may extend the full length of the supporting channel 62 orthey may extend only for a short distance corresponding to.

as shown in the d'raw- I the travel of the I-beam ings.

Hoists 58 are provided at opposite ends of the transfer device asperhaps best shown in Fig. 2,

and since the hoists are identical, a detailed de scription of but oneis given. Each hoist comprises a housing 10 having base flanges 12 whichare anchored solidly to the floor or other suitable support by bolts 14or the like. A pair of laterally spaced racks 16 are mounted forvertical sliding movement in the housing 70, and the upper ends of theracks extend above the housing and are fastened to respective channels62 by suitable mountings 78. The two racks 16 are raised and loweredsimultaneously by pinions on a shaft 82 which extends transverselythrough and is journaled for rotation in the housing 10. Intermediatethe: two pinions 80 is a driving pinion 84; and a horizontal rack 86,mounted for sliding movement in the housing 10, meshes with the pinion84 to rotatably drive the same. In order to relieve the various racksand pinions of excessive strain, a counterweight 88 is provided for eachof the vertical racks 76. In the form of the invention here shown, thecounterweights 88 are disposed in suitable guides'90 on one verticalwall of the housing 18 and are connected to their respective racks 16 byflexible ca-- bles 92, which cables pass through openings 94 in theupper portion of the wall and over pulleys 96 which are journaled forrotation in the openlugs 94.

As best shown in Fig. 2, the two horizontal racks-86 of hoists 58 areconnected for simultaneous operation by a connecting rod 98 so that allfour of the vertical racks l6 operate in unison.

Provision also is made for co-ordinating the slides and hoists of theseveral transfer devices 46. To this end, a rack I08 is fastened to thebottom flanges of each I-beam slide 54, and these racks mesh withpinions l02'carried by a common shaft I04 which connects the transferdevices 46and is journaled for rotation in suitable bearings I06 inchannel supports 62 (Fig. 3). Thus if any slide 54 is actuated, motionis transferred to the other slides in the assembly through the shaftI04. Asv a result, all of the slides 54- are positively connected forsimultaneous operation. Similarly, the horizontal shafts 82 of hoists 58are connected by suitable couplings I08 so that movement imparted to anyhoist automatically is transferred to the other hoists in the assembly.f V

. According to the present invention, drivingmeans is provided only forthe two middle transfer devices 46 and the two outer transfer devicesare driven through the coordinating mechanisms hereinabove described.Both the slides 54 and the two hoists 58 are operated pneumatically.

To this end, each of the middle'transfer devices 46 is provided with apneumatic cylinder and piston assembly, designated generally by thenumeral IIO, which is mounted between channels 62 with the piston actingagainst the transverse connecting member 64 (Figs. 2 and 3). Also, eachof the middle transfer devices 46 is equipped with a second pneumaticcylinder and piston assembly, designated generally by the numeral H2,which is mounted on a suitable support H4 beside one of the hoists 58with the piston connected to the adjacent rack 86 (Fig. 2). The pistonand cylinder assemblies of fluid motors III] and II2 are respectivelycontrolled by three-way valves H6 and H8 operated by solenoids I20 andI22 under control of limit switches LSI, LS2, LS3, LS4 and LS5. Theswitches LSI, LS3 and LS4 are of the normally open type closed by theirrespective actuators while the switches LS2 and LS5 are of the normallyclosed type opened by their actuators. Switches LSI and LS2 are carriedby one of the housings I and are actuated upon movement of the racks 86to their left-hand limit of movement, while switch LS3 also carried byone of the housings I0 is actuated upon movement of the racks 86 totheir right-hand limit of movement. Similarly, switches LS4 and LS arecarried by the support 56 and actuated at the left-hand and righthandlimits of movement of the slide 54.

More specifically, a pair of busses I24 and I26 energized from asuitable source of electrical energy upon closure of the line switchesI28 supply the control energy for the operating relays and solenoids. Aconductor I3Il having limit switches LSI and LS4, and a manually closedstart switch SW, connects one terminal of the energizing coil of a relayRI to the buss I24. The other terminal of this winding is connectedthrough a limit switch LS5 to the other buss I26 by a conductor I32. Aconductor I34 connects the buss I24 through normally open contacts a ofthe relay RI to the same terminal of the energizing winding as does theconductor I38 in by-pass arrangement to provide a locking circuittherefor so that once the relay BI is energized it will remain in thatcondition until opening of the switch LS5. One terminal of theenergizing winding of the solenoid I22 is connectedto the buss I24 byconductor l38'while its other terminal is connected by a conductor I38having normally open contacts I) of the relay RI to the buss I26. Aconductor I48 having the limit switch LS8 connects one terminal ofthe'energizing winding of a relay R2 to the buss I24, while a conductorI42 connects the other terminal of this energizing windingto the bussI26. A con-' ductor I44 having the limit switch LS2 connects the bussI24 through normally open contacts a of the relay R2 to the sameterminal of the energizing winding as does the conductor I40 in bypassarrangement to the switch LS3. A conductor I46 connects the buss I24 tothe normally open contactsb of relay R2 to one terminalof the energizingwinding of the solenoid I20; hav ing' its other terminal connected byconductor I48 to the buss I26.

The remainder of the details of the control circuit may best bedescribed by a description of its operation. With the racks 86 in theirleft-hand position and, consequently, the support 56 lowered and withthe slide 54 at its left-hand position with rsepect to the support 56,the switches LSI, LS4 and LS5 will be closed and the switches LS2 andLS3 will be opened as shown in Fig. '7. Assuming that the line switchesI28 are in closed circuit position so that the busses I24 and I26 areenergized, closure of the switch SWI will energize the relay RI throughthe closed switches LSI, LS4 and LS5. Closure of the contacts a of relayRI establishes a holding circuit for the relay RI in by-pass arrangementto the switches SW, LSI and LS4 which can now be opened withoutinterrupting the cycle of operation about to be described. Closure ofthe contacts b of the relay RI establishes a circuit from the buss I24through conductor I36, the energizing winding of the solenoid I22 andthe conductor I38 to the buss I26. Energization of the solenoid I22moves the valve II8 downward thereby admitting fluid pressure to theleft-hand pressure chamber of the fluid motor I I2 whereby the pistonI50 thereof is moved to the right causing the racks 86 to rotate thepinions 80 and 84 and drive the rack I6 in an upward direction raisingthe slide 54 and support 56 to cause the V-blocks 60 to lift the workfrom the V-blocks 52. Initial movement of the racks 86 and theconnecting rod 98 in a direction toward the right acts to open the limitswitch LSI without effect since the by-pass circuit through theconductor I34 and the contacts a of the relay RI is now closed and toclose the switch LS2 without efiect since the contacts a of the relay R2are now open. As the slide 54 reaches its uppermost position due to theracks 86 reaching their rightmost position, the limit switch LS3 isclosed thereby energizing the relay R2 through an obvious circuit andclosing contacts a and b of this relay. Closure of contacts a completesa holding circuit through the conductor I44 for the energizing windingof the relay R2 since the limit switch LS3 is now closed. Closure of thecontacts I) of the relay R2 completes an obvious energizing circuit forthe solenoid I20 whereby the valve H6 is moved downwardly to supplyfluid pressure through the left-hand chamber of the fluid motor I I0 sothat the piston thereof will move toward the right moving the slide 54relative to the support 56 in a right-hand direction, whereby therespective V-blocks 60 and the work supported thereby are transferredfrom one station to the next station. Upon initial movement of the slide54 to the right, limit switch LS4 is opened without efiect since therelay BI is energized through the by-pass conductor I34, Upon completionof the stroke of the slide 54 to the right, the limit switch LS5 isopened thereby deenergizing the relay RI permitting the contacts a and bthereof to open. The opening of the contacts a of the relay RI iswithout effect since the circuit therethrough was broken upon opening ofthe limit switch LS5. Opening of the contacts b de-energizes thesolenoid I22 so that the valve II8 may be moved upwardly by the springI50 permitting fluid pressure to be applied to the right-hand pressurechamber of the fluid motor H2 and to permit the fluid to exhaust fromthe left-hand chamber thereof.

- The racks 86 now move in a left-hand direction by the V-blocks 60 tobe received by the work supporting V-blocks 52. Initial movement of theracks 86 in a leftward direction opens the limit switch LS3 whichopening is without effect since a by-pass circuit therearound is madethrough the now closed limit switch LS2 and the contacts a of the relayR2. Upon completion of the leftward travel of the racks 86 andconsequent downward movement of the slide 54 and its support 56, thelimit switchLSI is closed without effect since the. switches LS4 and LS5are now open. The switch LS2 is opened thereby de-energizing the relayR2 causing its contacts a and b to open. Opening of the contacts bde-energizes the solenoid I20 permitting the spring I52 to actuate thevalve II6 back to the position shownwhereby fluid pressure is suppliedto the right-hand-pressure chamber of the fluid actuator III) and theleft-hand chamber is open to exhaust. 'The slide 54 now moves leftwardlywith respect .to the sup- .56 and the slide 54 permitting the workcarried Two V-blocks, I 64 should be provided in each station but theseblocks may be spaced various distances apart. For example, in the idlestations I54, I58, and I62 the V-blocks I64 are positioned to engage theaxle housing immediately behind the end flanges thereof; whereas, theV-blocks in work stations I56 and I66 are positioned to engage the axlehousing at the. outer sides of the flanges;

stations I56 and I60-the V-blocks are mounted on supporting arms I10which are fastened on the machines in such stations. In this connection,however, it will be readily apparent port 56 bringing the slide 54 backto its-original position. In its initial movement of the slide 54 towardits original position, the switch LS5 closes without eifect sinceswitchLS4 is still open. Upon completion of the movement to the originalposition, switch LS4 is closed and if the'manually operated switch SWIis still closed another cycle exactly the same as the one just describedwill be initiated whereby additional workpieces are transferred from onestation to the next station.

Theapparatus shown in Figs. 10-20 is adapted primarily for transferringaxle housings of automotive vehicles progressively and automaticallythrough a series of work stations designated generally by the numeralsI54, I56, I58, I60, and I62. In the form of the invention here shown,alternate stations I54, I58, and I62 are idle stations and the remainingstations I56 and I66 are occupied by machines which perform someoperation 6 on the workpiece.

The machines here shown in stations I56 and I60 are conventional andcomprise no part of the present invention.

In this connection, however, it will be readily apparent that thesequential relationship of the work stations is not critical; viz;, themachines need not be arranged alternately with respect to the idlestations. If desired, two or more machines may occupy adjacent positionsor two or more idle stations may be disposed between adjacent machines,depending upon the exigencies of the particular situation. Also,although five work stations" are here shown,v it will be readilyapparent that the apparatus can be adapted to a greater or lesser numberof stations. In each instance, the number of stations that, if'desired,aseparate supporting structure may be provided for the V-blocks' I66 inthose stations occupied by machines.

In this form of the invention, the transfer device is mounted above andextends the full length of work stations I54I62. A suitable 1 supportingframework'for the device is .provided,

will vary, depending upon the character ofthe I work being handled andthe nature of the oper 'ations to be performed thereon. It is essentialthat the work stations be arranged in alignment and that they be spacedequal distances apart; however, it is contemplated that severalapparatuses of the type here shown maybe used side by-side and inconjunction with means for transferring the workpieces from oneapparatus to another if a large number of operations are to be performedon the workpiece. I

Each work station is equipped with suitable stationaryworksupports uponwhich the workpiece rests, and the work supports in the various stationsare all arranged at a uniform height.

.In the apparatus here shown, the work supports .comprise spacedV-blocks I64 which engage the .axle housing workpiece I66 adjacent itsends.

and this framework is here shown in the form of-a plurality of inverted'U-shaped supports I12 which straddle the line of work stations and aredisposed substantially equidistantly therealong. Welded or otherwisefastened'substantially centrally to the crosspieces of supports I12 is alongitudinal stringer -I14. This framework can be fabricated'fromstructural members of any suitable size or shape and the elementsthereof are ,welded, bolted, or otherwise fastened solidly togethertoprovide an essentially-rigid structure. In the form of the in-vvention here shown, the supports I12 are made of I beams, and thestringer I14 comprises-a pair of channelsarranged backto back in spacedparallel relation.

The transfer device itself is suspended from the supporting structurehereinabove described and comprises a longitudinal slide support I16which extends across all five work stations and is suspended from thestringer I14 by a plurality of hoists I18. Carried by and depending fromthe slide support I16 is a slide member I which extends longitudinallyof the apparatus across four of the five work stations and is equippedwith a pair of work-holding members I82 for each of the four workstations. It will be observed that the slide I 86 is adapted to travelhorizontally with respect to the slide support I16 on a series ofrollers I64 and that the workholding members I82 in each pair arepositioned to engage opposite ends ofthe-workpieoe I66. Also, it will beobserved that the work-holding .members I82 are pivotally mounted on theslide I86 and that they are movable on their pivots is raised andlowered by the hoists I18. When the transfer mechanism is fully lowered,the portions of work-holding members I82 which engage the workpiece I 66are positioned below the terminal portions of the workpieces, and whenthe transfer mechanism is raised with the work-holding members closed,the workpieces are raised simultaneously from the stationary'worksupports I64. Suitable mechanism is provided for operating andco-ordinating hoists I18 so that they raise and lower the slide supportI16 and its appurtenances a distance sufficient to move the work-holdingmembers I82 from a position below the terminal portions of theworkpieces I66 to a position where the workpieces I66 carried bywork-holding members clear the stationary work supports I64. Manifestly,if the hoists I18 are raised with the work-holding members I82 closed,the workpieces I66 are raised from the stationary work supports I64 andtransposed to another station when slide I80 is moved horizontally;whereas, if the hoists are raised with the work-holding members open,the workpieces remain on stationary supports I64 and the transfer deviceis raised sufficiently to clear the workpiece when the slide I80 ismoved horizontally. Mechanism also is provided for translating the slideI80 a distance equal to the distance between adjacent work stations,which mechanism is operable only when hoists I18 are raised but with theworkholding members I82 either opened or closed.

Initially, hoists I18 are in lowered position with the slide I80 inretracted position above the first four work stations I54, I56, I58, andI60 and with the work-holding members I82 open. In a typical cycle ofoperation all of the work-holding members I82 are first closedsimultaneously to engage all four workpieces I66 in stations I54, I56,I58 and I60, and hoists I18 are then raised to lift the workpiecessimultaneously from the above stations. When the hoists I18 are fullyraised, slide I80 is actuated to move all of the workpieces I66 onestation to the right. as viewed in the drawing (Figs. A and 10B). HoistsI18 are then lowered to deposit workpieces I66 inthe adjacent stationsI56, I58, I60, and I62 respectively, and the work-holding members I82are opened to disengage the workpieces. Hoists I18 are then raised,slide I80 retracted to its initial position, and the hoists lowered withthe work-holding members I82 open to complete the cycle of operation.

Control mechanism may be provided for performing the series ofoperations described above automatically either continuously orperiodically at fixed intervals, or, alternatively, the controlmechanism may be made to operate only under the control of a manualstarter switch and to perform the series of operations automaticallyonly when the starter switch is operated.

After each cycle of operation, a new workpiece is placed either manuallyor automatically on the stationary work supports I64 of work stationI54, and a workpiece is removed either manually or automatically fromthe work supports of station I62.

Each of the hoists I18 is identical in construction and operation, and adetailed description of one therefore will suflice. For this descriptionreference is had to Figs. 11 and 12 wherein the numeral I86 designates ahousing for a rack I88 and a pinion I90. The housing I86 is arrangedbelow the stringer channels I14 and is fastened solidly thereto by boltsI92. Within the housing I86 and disposed substantially midway betweenthe channels I14 is a vertical bore I94 which receives the rack I88, andsleeve bearings I86 are provided in opposite ends of the bore toslidably support the rack. Rack I88 extends entirely through the housingI86, and a cap I98 is fastened to the upper end thereof to limitdownward movement of the rack. On the projecting lower end of rack I88are brackets 200, which brackets are fastened to the slide carrier I16by bolts 202 or 'gether by cross plates 234.

the like. A plate 284 interposed between brackets 200 and slide carrierI16 hold the two channels which make up the carrier in fixed spacedrelation. The pinion I90 is keyed on a stub shaft 206 which is rotatablysupported in the housing I86 by roller bearings 208. Packing glands 2 I0around the projecting terminal portions of stub shaft 62 and fastened tohousing I86 by bolts 2I'2 retain the bearings 208 and prevent lubricantin the housing from escaping along the shaft. As best shown in Fig. 11,the pinion I90 is disposed in a chamber 2 I4 which opens exteriorly ofthe housing and communicates at right angles with bore I84. The pinionis inserted in housing I86 through the open outer end of chamber 2 I4,and 2h: latter is normally closed by a removable plate 'In operation,the pinion I90 is rotatably driven to raise or lower the rack I88. Itwill be readily apparent that actuation of the rack raises or lowers theslide carrier I16 and its appurtenances.

In order to co-ordinate the hoists I18, connecting rods 2I8 are insertedbetween the pinion shafts 206 of the various hoists and connectedthereto by suitable couplings 2 I 8. Thus, rotation of the shafting 206,2I8 operates the hoists I18 in unison.

In the form of the invention here shown by way of illustration, hoistsI18 are operated by means of a fluid motor 220 which is mounted on thestringer I14 at substantially the middle thereof. Fluid motor 220comprises the usual cylinder 222 and a piston (not shown) having theusual piston rod 224. The latter extends downwardly from the cylinderand carries a rack 226 which meshes with a pinion 228. Both the rack 226and pinion 228 are mounted in a suitable housing 230 which is generallysimilar to the housings I86 hereinabove described. The housing 238 isdisposed below and bolted to the stringer I14 in alignment with thefluid motor 220 (Fig. 19). Pinion 228 is keyed or otherwise fixed on ashaft 232 which is coupled in the shafting which operates the hoists I18(Fig. 10A).

Manifestly, when the fluid motor 220 is operated to move piston rod 224and rack 226 downwardly, pinion 228 drives the shafting 206, MB, and 232in a clockwise direction, as viewed in Fig. 19, to raise hoists I18 andthe work transfor device carried thereby. Alternatively, operation ofthe fluid motor 220 to raise piston rod 224 and rack 226 rotates thepinion 228 and the shafting associated therewith in a counterclockwisedirection, as viewed in Fig. 19, to lower the hoists I18 and thework-transfer device carried by the hoists.

. The slide I 88 comprises a pair of channels arranged back to back andin spaced parallel relation as shown in Fig. 14 and held rigidly to- Assuggested, the slide I extends over four of the five work stations andis movable from a position above stations I54, I56, I58, and I60 to aposition above stations I56, I58, I60, and I62. Cross plates 234 areprovided with upstanding arms 236 (Fig. 10A) which carry the rollersI84. As suggested, sets of rollers are provided at longitudinally spacedintervals along the slide; and there are two rollers in each set, whichrollers ride on the lower flanges of respective slide-supportingchannels I16.

Slide I80 is actuated by a fluid motor 238 (Fig. 18) which comprises theusual cylinder 240 and a piston (not shown) having a piston rod 242.

On the distal end of the piston rod 242 is a rack 244 which operates insuitable guides 246 and aotuates a second rack 248 through the medium ofa small gear 258 disposed between the two racks. As clearly shown in thedrawing, the fluid motor 238 and rack 244 are mounted between andcarried by the two carrier channels I16, and the rack 248 is fixed tothe slide I88.

When piston 242 is advanced, rack 244 is moved to the right, as viewedin Fig. 18, and pinion 258 is rotated in a clockwise direction to moverack 248 to the left. Manifestly, slide I88 will move with the rack 248.Conversely,retraction of the piston rod 242 moves rack 244 to the left,

as viewed in the drawing, and rotates the pinion 258 ina-counterclockwise direction to move rack 248 and its appurtenances tothe right. As suggested, the stroke of piston 242 is sufficient to movethe slide I88 a distance equal to the distance between adjacent workstations.

With reference to the work-holding, members I 82, it will be observed(Fig. 15) that. the two supporting channels I88 are held in fixedrelation by spacers 252 and that the channels are bolted or otherwiseheld solidly together. A pair of work-holding members. I82 is providedfor each'work station covered by the. slide I88, and

each work-holding member is pivoted to a supporting bracket 254 which inturn is weldedor otherwise secured to the slide I 88. As best shown inFig. 16, members I82 are arranged vertically on horizontal pivots andthe lower ends'thereof carry blocks 256 which project laterally tosupport a terminal of the workpiece I66, An actuator linkage connectsthe upper ends of each pair of work-holding members and means isprovided for operating the linkage to open and close the members in themanner hereinabove described,

viz., to movethe work-holding members between the fulland broken-linepositions in .Fig. 16.

Specifically, each linkage comprises a relatively short lever 258 whichis disposed between the two channels I88 and substantially,midwayvbetween the two work-actuating, members 182. Lever 258 is keyed orotherwise fixed on a shaft 268 which is journaled in a mounting attachedto one of the channels I 88. The ends of lever 258 are connected torespective work-holding members I82 by links 264, and each link isconnected to its respective work-holding'member by a lostmotionconnection designated generally by the numeral 286,

When the shaft 268 is rotated to position lever 256 substantiallyhorizontally, as shown by broken lines'inFig. 16, the links 264 closethe 11.4 work-holding members by a pneumatic actuator means. For thispurpose a fluid motor 268 is bolted to a mounting plate 218 at one endof the slide I88 with'the piston rod 212 disposed behind andparallel tothe channel which carries the stub shafts 268. Preferably the mountingplate 218 extends beyond the motor 268, and the projecting portionthereof forms one of the spacers 252 as shown in Fig. 15. Each of thestub shafts 268 is provided with a pinion 214 and aligned racks 216 meshwith these pinions. a guide assembly 218 which is welded on-the.adjacent channel I88, and the racks are con nected to each other and tothe piston rod 212 by suitableconneeting rods 288.

From the foregoing it will be readily apparent that, when piston 212 isretracted, racks 216 are moved simultaneously to the left-hand limits oftheirtravel and stub shafts 268'are rotated in a clockwise direction, asviewed in Fig. 16, to close the work-holding members 282. Conversely, advancement of piston 2'12 moves the racks 218 in unison to the right asviewed in Fig. 15 and rotates'the stub shafts 268 in a counterclockwisedirection to open the work-holding members I82. Since all of the racks216 operate in unison, all of the pairs of work-holding members operatesynchronously.

In the'form of the invention here shown, each work-piece I 66 issupported middle by a holding pad 282 which is suspended from and boltedto'a mountingblock 284 on the slide I881 The mounting bolts 286 whichhold pad 282 on the block 284 permit limited movement of'the-padrelative to'the mounting plate, and spring means 288 interposed betweenthe mounting and pad urge the latter downwardly against the workpieceI66. By reason of the springpressed engagement between pad 282 and workpiece I66 the latter is held in a selected rotatably adjusted positionin the work holders I82.

The control system for the modifiedform of transfer apparatus shown inFigs. 18 through 20 comprises three-way valves-288, 296, and 382 forcontrolling the flow of pressure fluid to the fluid motors 268,228, and238 respectively. Each of the valves is operated by a pair of solenoids292-294, 298-388, and 384'386 respectively. The valves 298, 286, and 382are each of the type in which the energization of one of itscontrollingv solenoids will actuate the valve into-the respectivecontrollingposition after which the valve will reholding members I82.Conversely, when shaft 268 is rotated tomove the lever 256 to theposition shown by full lines in Fig. 16, links 264 pull the attachedends of work-holding members I82 toward each other and rock such membersabout their pivots to the fullor open-line position. In the latterposition, work-holding members I82 release the workpiece I 66.

It may thus be seen that both work-holding members I82 in each pair areoperated in synchronism and that they are opened or closedsimultaneously. Also, by reason of-the instant arrangement, the actuatorlinkage is positioned between and protected by the spaced slide channelsI88. In this connection, it will be readily .apparent that the strongrigid slide provides an excellent support for' the work holderspand theactuator mechanism and that the entire structure is compact andexceedingly strong. 7

According to the present invention, the pairs of main in that positionirrespective of the con- .tinued 'energization thereof until such timeas the other of its controlling solenoids is energized. Theenergization: of the various solenoids is controlled by a series ofnormally open limit switches are actuated to closed position at the endlimits of travel of the'various movable members.

Limit switches LS-? and LS-8 are actuated re spectively whenthework-holding members are in a releasedand a work-holding position andare with the fluid motor 258. Limitswitches LS4! andLS-i8 carried by theslide'support I16 are actuated respectively upon movement of theslidelail to its left-hand and its right-hand positions by abutments 388and 3 I8 carried. by the rack 244. Limit switches LS-II and'LS-IZ,carried by the housing I88 of the hoist I18, are engaged by an abutment3H2 carried by the. rack I 88 for actuation thereof upon'downward' andupward movement respectively of the work-carrying slide I88. The limitI82 are operated together Each rack 216 is slidably mounted in Isubstantially at its switch LS-l2 is of the double-circuit-controllinstype having two independent sets ofnorrnally open contacts LS-l'aa andLEAR), each being arranged to be moved to closed position upon actuationof the limit switch LS-(Z by the abutment 3l2.

A manually operable starting switch SS-! is moved to closed position tostart the cycle of operation which comprises actuating the workholdingmembers or hooks Hi2 into work-holding position with respect to theworkpiece 55, actuating the hoist 6TB to lift the workpieces E53upwardly, actuating the slide member 80 to move the workpieces H56horizontally to the next station, actuating the hoists 118 to lower theworkpieces E96, actuating the hooks 82 to move them out of work-holdingposition with respect to the workpieces I56, actuating the hoists lit toraise the hooks I32, actuating the slide member I86 whereby it isreturned to its left-hand position, and actuating the hoists {7-8 tolower the hooks H32 into a position in which they are in a position tobe actuated for lifting the next workpiece I65. As each of the foregoingsteps is completed, limit switches LS-l' through LS-l2 are actuated,whereby the series of steps is carried on automatically without furtherefiort on the part of the operator. 1

Power from a suitable source of supply is supplied to the bus conductors3M and 316 through usual line switches Bit! and 329 respectively. Oneterminal of the energizing winding of the solenoid 292 is directlyconnected to the bus 314 while the other terminal is connected throughthe start switch SS4 and contacts a of a work-cycle control switch WS-lto the bus 3H5. One terminal of the energizing windingof the solenoid294 is connected directly to the bus 3M while the other terminal isconnected through the contacts I) of the switch WS-l and through thecontacts a, of the control relay CR-l to the line 316. Likewise, oneterminal of each of the energizing coils of the solenoids 298, 399, 304.and 396 is connected to the bus conductor 314. The other terminal of theenergizing winding of the solenoid 298 is connected to the bus 318through two parallelly arranged conductors 322 and 324. The conductor322 has therein the contacts a of the control relay CR4 and the contactsa of the control relay CR ri. The conductor 324 contains the contacts aof the control'relay Cit-3 and the contacts a of the control relay CR-B.The other terminal of the energizing winding for the solenoid 303 isalso connected through two parallelly extending conductors 326 and 328to the bus conductor 3I6. The conductor 325 contains the normally opencontacts b of the control relays CR-3 and CR-B while the conductor 328contains the normally open contacts b of the control relays CR4 and CR4.The other terminal of the energizing winding for the solenoid 3% isconnected through the normally open contacts LS-l2a and the normallyopen contacts 0 of the control relay CR;-3 to the bus conductor 3H5.Likewise, the other terminal of the energizing winding of the solenoid395 is connected through the normally open contacts LS-iZb and contacts0 of the control relay CR-t to the bus conductor SIB. A conductor 339 isinterconnected between thebus conductors 3M and 3l6 and has therein-thelimit switch LS-ll and the control winding for the control relay CR-l. Aconductor 332 isalso connected between the bus conductors 3M and 319 andhas therein the limit switch LS-9 and the energizing winding for thecontrol relay CRr-G.

Likewise conductors 334, 336, and 338 are also connected between the busconductors 3H!- and 316 and have respectively therein the limit switchLS-l t and the energizing winding for the control relay (IR-5, the limitswitch LS-i and the energizing winding for the control relay CR-B, andthe limit switch LS-S and the energizing winding for the control relayCRPA. It is believed that the remaining details of the electricalcircuit for the invention as illustrated in Figs. 10 through 20 may bestbe understood by description of operation which is ,as follows: 3

Upon closure of the switches SH! and 320 the conductor busses-3l4 and319 will be energized with electrical potential from a suitable sourceof supply. Since at the end of each cycle of operation the slidel89'will be lowered and in its lefthand position and the hooks I82 willbe open, the limit switches LS-l, 16-9, and LS-! i will be actuated andmaintain the relays CIR-3, CR-B, and CR-l energized. Energization of therelays CRF3 and CR-B completes an energizing circuit for the solenoid398 through the now closed contacts b thereof. The work cycle controlswitch will normally be in its'shown position with the contacts Inclosed so that the closure of the contacts a of the relay CRHI will actto energize the solenoid 294, whereby the hooks I82will be maintainedout of work-engaging relation. If by any possible chance the hoist H8should be elevated at the time the line switches 3i8and 320 were closed,the limit switch LS-l2 will be closed; and since the contacts c of thecontrol relay CR-3 are also closed due to the aforesaid energization' ofthe relay CR-3 the solenoid 386 will be energized to provide thenecessary actuation for the fluid motor.233 whereby the hoist H8 isactuated to lowered position closing the limit switch LS-H forenergization of relay CRFI.

When it is desired toinitiate a cycle of operation of the transferapparatus, the work cycle control switch WS-! is moved to its upposition whereby contacts a thereof are closed so that when the startingswitch S84 is closed, an obvious energizing circuit for the solenoid 292will be closed, The switch WS-l may be moved to its up position manuallyor such movement may be the consequence of some other associatedfunction such as the completion of a machining or other work operationat the various stations. It mayfurther be stated that the switch W-S-lis actuated to its shown or down position at some instant after thelimitswitch LS-ll has opened 'due to upward movement-of the hoistllB andbefore the workpiece has been completely lowered into its next position.Again this actuation of the switch WS-l to down position may be as aconsequence of the movement of the workpiece or of the transferapparatus or maybe manual, as desired.

Closure of the starting switch SS-l establishes an obvious circuit forthe solenoid 292 through the now closed contacts a of the switch WS-lwhereby the valve 299 is moved in an upward direction so that fluidpressure is applied to the fluid motor 238 for moving the connecting rod212 thereof in a direction toward the left which, as statedhereinbefore, will 'actto close the hooks 132 against the ends of aworkpiece I65. Initial movement of the fluid motor 288 to the left willcause the limit switch LS-T-to open, thereby deenergizing the controlrelay VCR-3 and opening the contacts a, b, and 0 thereof. Opening thecontacts a is without effect since the control relay CIR-5 is nowtie-energized and the contacts a .thereof are open, breaking thecircuit-through the conductor 324. Opening of the contacts b ofthecontrol relay CR-t de-energizes the solenoid 300, which circuit waspreviously completed through the conductor 32B and the closed contacts bof the control relay (IR-6 under control of the limit switch LS-S.Opening of the contacts of the control relay CR-3 is without effectsince the contacts LS-i2a are already in open position;

As the fluid motor completes its stroke to the left, the limit switchLS-8 will be 'closed, completing an obvious energizing circuit for thecontrol winding of the relay CR- l, causing the contacts a, b, and 0thereof to be closed. Closure of the contacts a completes an obviouscircuit through the conductor 322- for the solenoid 298 since thecontacts a of the control relay CR-B .are at this time closed due to theclosed 'con- CHI-5 are now open circuited due to the opencircuitcondition of the limit switch LS-IO' and due to the open-circuitconditions of the con tacts LS-l2b of the limit switch L842. Y

Initial movement of the hoist H8 in an up.- ward direction opens thelimit switch LS4! which de-energizes the energizing winding of thecontrol relay CR-l causing the contacts a thereof to open without eifectsince the. contacts I) of the switch WSV-l were already in opencircuitcondition as before described, maintaining the solenoid 294.de-energized. Upon completion of the movement of the hoist in an upwarddirection, the limit switch LS-l2 will be actuated and the contactsLS-l2a and LS-I2b thereof moved to closed position. Closure of thecontacts LS-l2b is without effect, since the contacts 0 of the controlrelay CR4 are now in open-circuit position. Closure of the contactsLS-lZa, however, completes "an obvious energizing circuit for thesolenoid 304 through the now closed contacts 0 of the control relay CR-l. Energization of the solenoid 3,04 moves the control valve 302 in itsupward position in which fluid pressure is supplied to the fluid motor238 to move the piston and piston rod 242 thereof.

Initial movement of the rod 242 in a lefthand direction causes the limitswitch LS-9 to open, thereby de-energizing the control relay CR-6whereby the contacts a and b thereof move to open position. Opening ofthe contacts a of the relay CRFB de-energizes the solenoid 298 withouteffect. Opening of the contacts b of the control relay CR-B is withouteffect,'since the circuit through the conductor 326 is already broken,due to the open-circuit condition of the contacts I) of the relay CR-3.Upon completion of the movement of the piston rod 242 contacts b of theswitch to .lower the hoist I18.

the limit switch LS-l.

300 without effect. prepare the valve 296 for operation by the stroke ofthe fluid ;LS-l' will be closed thereby energizing the energizingthetsolenoid 300, since the contacts b of the relay CR4 are now in closedcondition due to the closed-circuit position of the limit switch LS-T.Energization of the solenoid 300 'is'fsupplied to the lower side of thepiston to move the piston rod 224 in an upward directionInitial'movementof the hoist H8 in a down ward direction opens theswitch LS-i2 whereby the contacts LS-lZa and'LSl2b thereof are open.Openingof the contacts LS-l2b is without effect since the contacts CR-3care already in open-circuit condition. Opening of the contacts LS-lZa.de-energizes the. solenoid 304 since the contacts 03-40 are inclosedircuit position due to the closed condition of As stated withrespect to the de-energization of the solenoid 298, the

LdeI-e'nergization of the solenoid 304 is without effect upon the valve302, except as tov place it in condition for operation by the solenoid306 as will be subsequently described. Upon completion of the downwardmovement of the hoist I18 the limit switch LS-ll will be closed, therebyre-establishing a circuit through the conductor 330 and re-energizingthe control winding of the relay CR-l causing the contacts .d thereof tomove to closer position. Since the WS-l are now closed, the closureofthe. contacts CR-la will energize the solenoid 29 moving the valve 292to its lower positionas shown inthe'drawing whereby fluid pressure is.supplied to the fluid motor "268: for movement of the piston 'rod 212 ina tactsa, is without effect, since the circuit through the conductor 322has already been broken by the open condition of the contacts a of therelay CRJ-G." Opening of the contacts'b of the relay CR- i de-energizesthe circuit through the conductor 328 which de-energizes the solenoidHowever, such action does solenoid 298. Opening of the contacts 0 of therelay CR is without effect, since the contacts LS-l2a are already inopen-circuit condition. Upon completion of the right-hand motor 268,'thelimit switch control winding of the causing the contacts close.

control relay Cl-t-3 a, b, and 0 thereof to Closure of the contacts aenergizes the 'fsolenoid 298 through the now closed circuit of conductor324, since the contacts a of relay to the left, the limit switch LS-IOwill be actu Iated and closed thereby establishing an obvious energizingcircuit for the control winding of the .circuit through the conductor324 is also broken at the contracts a of the control relay CR-3.

Closure of the contacts CR-Sb completes, however, acircuit through theconductor 328 for of the limit switch LS-IO.

grelay gen-3 1 is {condition of thelimit switch LS-H.

(JR-5 are closed due to the closed condition The valve 296 is 'rnov'edto its upward position whereby fluid pressure is supplied to thefiuid'motor 2?.ilfor moving the rod 224 thereof in a downward directionraising the hoist [.78.

. Closure of the contacts b of the relay CR-3 is without effect,sincethe contacts b of the relay (JR-6 are open,

,due to the open-circuit condition of the limit switchLS-B. Closure ofthe contacts 0 of the without effect due to the open Initialupwardmovement of the hoist I18 opens the switch LS -l-l whereby thecontrol relay CR-l pressure is supplied to sagas LS-8 is now opened andthe contacts c'of the control relay CR-l are now in open-circuitposition. Closure of the contacts LS-l2b completes obvious energizingcircuit for the solenoid 306,

are now closed due to the closed condition of the limit switch LS-I. Eergizatien of the solenoid 306 moves the valve 302 to its position asshown in the drawings, whereby fluid pressure is supsame as thatinitially described in which the hoist I18 is down, the slide member I80is in its left-hand position, and the hooks I82 are in open position. Torestart a transfer cycle the switch WS-I is moved to close its contactsa and the start switch SSV-I closed.

It may now be seen that there is provided an automatic system in whichclosure of the starting switch SS-I will initiate a complete series ofoperations in which the workpieces are engaged by the hooks I82, arelifted by the hoist I18, are

since the contacts of the control relay 'CR -3 plied to the fluid motor238 for move ent the piston and rod 242 thereof in a right-hand direc'-tion to cause the slide I80 to move in "a left-hand direction.

Initial movement of the slide 1 B0 in aloft-hand direction or the pistonrod 242 in a right-hand direction causes the contacts L's-I0 to open,thereby de-energi'zing the control relay QR-"S. Opening of the contactsaof the relay'CR-o acts to 'de-energize the circuit through theconductor 32! and the now closed contacts a of the relay CR-3 therebyde-energizing the solenoid 208 without effect upon position of the valve296. Opening of the contacts I) of the relay CR-S is without effect,since the contacts b of the relay CR-l have reviously been opened due tothe opening of the limit switch LS-8. Upon completion of the stroke ofthe slide member I80 to the left or the stroke of piston rod 212 to theright the limit switch LS-9 will be closed thereby completing an obviousenergizing circuit for the control relay CR-B whereby the contacts aand 1) thereof will be moved to closed position. Closure of the contactsa is without effect, since the circuit through the conductor 322 is nowopenby'the open contacts a of the relay CR- -fl due to the open limitswitch LS-8. Closure of the contacts b of the relay CR-6 establishes acircuit through the conductor 326 and the now closed contacts I) or therelay CR-3 whereby the solenoid 300 is energized moving the controlvalve 296 to its lower position as shown in the drawing, whereby fluid Vthe fluid motor 220 Ifor moving the piston rod 224 thereof in an upwarddirection and lowering the hoist I18. 7,

Upon initial movement of the hoist I10 in a downward direction, thelimit switch LS-I2 will be opened, opening the contacts LS-I; and LS-I2bthereof. Opening of the contacts L's- 12a is without efiect due to theopen-circuit condition moved to the right under control of the slidemember I80, are lowered by the hoist I18, and are released by the hooksI82 at the next work station. The hoist I78 then raises thework-carrying member, moves it to the left along the slide member I80,and lowers it at the original station with the hook members I82 openready for reception of a new workpiece.

Having thu described the invention, I claim:

1. A mechanism for transferring workpieces through a series ofequispaced stations comprising work-supporting means associated witheach of said stations and disposed in substantially aligned equispacedrelation, pairs of pivoted work-carrying arms for said stations arrangedwith the pairs of arms spaced according to the spacing of saidwork-supporting means, each pair of arms positioned to straddleworkpieces on the work-supporting means of a station and movable toengage or release the terminal portions of said workpieces, means forsimultaneously actuating said arms between engaged and releasedpositions, an elongated slide common to "and carrying all of saidwork-carrying arms "mounted to travel in a direction substantiallyparallel to said series of stations for moving each pair ofwork-carrying arms back and forth from one station to another, and ahoisting mechanism carrying said slide for moving the latter togetherwith the work-carrying arms associated there- 'with vertically withrespect to said work -supporting means.

2. A mechanism for transferring workpieces through a series ofequispaced stations comprising work-supporting means associated witheach of said stations and disposed in substantially aligned equis'pac'edrelation, pairs of workcarrying arms for said stations arranged with ofthe contacts 0 of the relay CR-4 under control p or the open-limitswitch Ls-a. Opening "of the contacts LS-I2b tie-energizes the circuit'forthe solenoid 306 through the now closed contacts 0 of the relay CR-3under control of the "closed limit switch LS4. De-energization of thesolenoid '306 is without effect upon the position ofthe control valve302. 'Upon completion of the'movement of the hoist I18 in a downwarddirection the switch LS-II is closed, thereby establishing an obviousenergizing circuit for'the control relay I CR-I whereby its contacts aare closed without effect since the work-cycle control switch WS I isnow in its upward position and the contacts 2: thereof are opencircuited. Upon completion of the before-described steps, the apparatus,"will stop and stay in 'thefin'al position which is the the pairs ofarms spaced according to-the spacing of said work-supporting meanspositioned 'to straddle a workpiece on said work-supporting means andprovided with V blocks movable under the terminal portions of saidworkpieces, an elongated slide common to and carrying all of saidwork-carrying arms mounted to travel in a direction substantiallyparallel to said series of stations for moving said arms back and forthbetween adjacent stations, a hoisting mechanism carrying said slide formoving the latter together with the work-supporting means car- 'riedthereby vertically with respect to said worksupp'orting means, andspring-biased pressure pads carried by and movable with said slide en-'gageable with the workpieces intermediate the ends thereof when thehoisting mechanism is operated to lower the slide, said pressure pads'being engageable with the workpieces before the V "blocks arepositioned to engage under theends of the workpieces whereby said padspress the workpieces downwardly against the V blocks when the hoistingmechanism is operated to raise the slide.

V "3. A mechanism for transferring workpieces through a series of"stations comprising work ward projections engageable under the terminalportions of said workpieces, means for, actuating the arms in each pairtoward and away from each other and into and out of engagement with aworkpiece, means co-ordinating said actuator means for simultaneousoperation, an elongated slide commonto and carrying all of saidwork-carrying arms mounted to travel in a direction substantiallyparallel to said series of stations for moving each pair of saidworkcarrying arms back and forth between said stations, and a hoistingmechanism carrying said slide for moving the latter together with thework-carrying arms associated therewith vertically with respect to saidwork-supporting means.

RALPH E. CROSS. 7

References Cited in the file of this patent UNITED STATES PATENTS NumberPlatz Aug. 13, 1942

